A Brief History of Genetics

1
A Brief History of Genetics

• Important developments in the 19th and 20th
  centuries

2
The 19th Century

• 1850s Gregor Mendel develops 3
  principles -Segregation -Independent
  Assortment - -Dominance
• 1859 Darwin publishes The Origin of Species
• What is heredity? What traits are heritable?
• 1869 DNA is isolated

3
What is the hereditary material?

• Protein
• 20 different monomers
• Present in eukaryotic chromosomes
• highly variable structures and functions

• DNA
• 4 different monomers
• Present in eukaryotic chromosomes
• Limited variability (?)
• function unknown

4
Early 20th Century

• 1902 Walter Sutton-chromosome theory of
  inheritance
• 1907 Thomas Hunt Morgan- sex linkage, mutation
  theory recombinant frequency mapping
• 1920 Nucleotide structure
• 1928 Frederick Griffith Transformation

5
Griffiths Experiment
6
The 1940s

• 1941 Beadle and Tatum one gene---gtone enzyme
• 1944 Avery, McCleod and McCarty identify DNA as
  the transforming principle but
• 1945 Max Delbruck and Salvador Luria The Phage
  Course at Cold Spring Harbor
• 1947 Barbara McClintock transposable elements

7
The 1950s

• 1950 Irwin Chargaff- Chargaffs rules
• 1952 Alfred Hershey and Martha Chase The
  Blender Experiment
• 1952 Joshua Lederberg plasmids and bacterial
  recombination
• 1953 Watson, Crick, Wilkins and Franklin DNA
  Structure
• 1957 Meselson and Stahl semiconservative
  replication
• 1959 Jacob Monod Genetic regulation Operons

8
Hersheys and Chases Blender Experiment
9
Watson and Cricks DNA structure
10
DNA Replication
11

• Meselson and Stahls Mechanism Semiconservative
  Replication

12
And the winners are..

• 1933 Morgan
• 1954 Pauling (also 1962)
• 1958 Beadle Tatum AND Lederberg
• 1962 Watson, Crick and Wilkins
• 1965 Jacob, Lwoff and Monod
• 1969 Delbruck, Luria and Hershey
• 1983 McClintock